automatic gearbox problems

Hi guys I am doing some work on a disco 1 300tdi auto at the minute about a week ago I changed the oil and filter and it was perfect its done probably 100 miles since and this morning got a phone call yesterday it was perfect from cold it would change gears etc, it would do the normal auto thing and hold the revs a bit longer because the engine is cold but now until the engine is warm it will hold 1st gear and not change at all he said it will go to 4000 rpm and a bit more and just hold there until the engine is at normal working temperature after that it changes and is all nice and smooth and operates as it should, am I right in thinking the brain for the gearbox has a loose wire or something any help appreciated

Double check the oil level when cold, idling in neutral after you have held it in each gear for 5 seconds.
Check the both sides of the dipstick as sometimes it will give a false reading on one side of the stick as you pull it up the tube.

disco 1 is mechanically governed ,changing oil on a old box can give govenor issues ie not changing up till box is upto temp ,atf is very detergent and can over clean spools , it may improve in time otherwise govenor will need looking at

Cut from Ashcroft Transmission's site

I have a 4 speed ZF Auto and it sticks in first gear in the morning or when cold and is reluctant to change up from 1st gear. Once the gearbox has warmed up it shifts normally. Why?

The governor valve is sticking, which can be caused by contamination. i.e. clutch plates or other parts disintegrating. The fine debris finds its way past the filter and tends to accumulate in the governor, causing it to stick. A temporary solution is to remove and clean the governor. The problem will often recur as debris from damaged parts continues to build up in the governor. If the problem continues after cleaning the governor then it may be necessary it replace your Autobox.

We have noticed many customers reporting this fault starting a few days after an oil and filter change and after researching this using our experience and the expertise of others in the trade we have come to the conclusion that as ATF oil is a detergent type oil, when the oil is changed this will dislodge and stir up settled debris in the autobox which in turn jams the governor valve. In light of this although it sounds controversial it is debateable if changing the oil and filter is a good idea, some say if the box it going to fail it will fail if the oil is good or bad and their advice is leave it alone. I am still undecided but the truth is I get a lot of calls from customers thinking they are looking after the autobox by servicing it and a few days later this fault occurs.

thanks guys looks like im going to have fun either ripping the box out and putting a new one in or setting fire to the f$*king thing, I have to make this disco in to a fully prepped motor for off road tours from a standard disco

governor can be removed without removing auto box

thanks is there an easy way or break out manual and try and work it out for myself and have fun and where is the blooming thing as I don't know where it is